Happy 75th anniversary, women’s jeans!

Thursday was the 75th anniversary of when Levi Strauss & Co. created the first 701 denim jeans for women — bringing the comfortable, durable clothing to the other half of the population. (Men’s jeans had been around long before.)

“Levi Strauss & Co.’s decision to create a line of women’s Levi’s jeans was very progressive at the time,” Lynn Downey, historian for Levi, said in a statement. “Pants still weren’t an acceptable part of a woman’s wardrobe, let alone a style of pants considered to be men’s workwear.”

Now pairs of jeans have become staples — must-haves in women’s wardrobes. Indeed, in this tough economy, jeans have “been the one salvation for apparel retailers,” according to a story by Reuters.

So slide on your favorite pair of denims in honor of this day, ladies, and share with me your favorite cut or brand of jeans by posting a comment below. (After the jump, here:

The evolution of women’s jeans, according to Levi’s:
— Pre-1934: Women in the West began wearing their husbands’ or brothers’ Levi’s® 501® jeans, the original blue jeans first created in 1873. These pants were sturdy enough to handle the rough life of a rancher.

— 1934: The first pair of women’s jeans, Lady Levi’s®, are created. Assigned lot number 701 to distinguish them from men’s jeans (Lot 501), the original pairs were aimed at women working on ranches and sold in several Western states.

— 1930s and 1940s: Sales of women’s jeans begin to take off due to the growing popularity of dude ranches. High-end department stores Best & Co. and H. Kauffman & Sons Saddlery Company carried Levi’s jeans to meet this new demand. Women’s jeans also switched from button-fly to zipper.

— 1960s: Amid a tumultuous cultural revolution, denim becomes a staple in women’s wardrobes. Jeans become a icon of rebellion that’s adopted by both men and women. Levi’s introduces a slimmer fitting jean – the precursor to the modern Skinny jean. Stretch women’s jeans became popular among teenage girls.